Add Collapsible match lint
changelog: Add collapsible_match lint
Closes#1252Closes#2521
This lint finds nested `match` or `if let` patterns that can be squashed together. It is designed to be very conservative to only find cases where merging the patterns would most likely reduce cognitive complexity.
Example:
```rust
match result {
Ok(opt) => match opt {
Some(x) => x,
_ => return,
}
_ => return,
}
```
to
```rust
match result {
Ok(Some(x)) => x,
_ => return,
}
```
These criteria must be met for the lint to fire:
* The inner match has exactly 2 branches.
* Both the outer and inner match have a "wild" branch like `_ => ..`. There is a special case for `None => ..` to also be considered "wild-like".
* The contents of the wild branches are identical.
* The binding which "links" the matches is never used elsewhere.
Thanks to the hir, `if let`'s are easily included with this lint since they are desugared into equivalent `match`'es.
I think this would fit into the style category, but I would also understand changing it to pedantic.
add `internal-lints` feature to enable clippys internal lints (off by default)
This PR moves the internal lint tests into a new subdirectory (I couldn't find a different way to compile-time-conditionally exclude them from compiletest) and only builds and tests internal lints if the `internal-lints` feature is enabled.
Fixes#6306
changelog: put internal lints behind a feature ("internal-lints")
Update error to reflect that integer literals can have float suffixes
For example, `1` is parsed as an integer literal, but it can be turned
into a float with the suffix `f32`. Now the error calls them "numeric
literals" and notes that you can add a float suffix since they can be
either integers or floats.
Part of #68490.
Care has been taken to leave the old consts where appropriate, for testing backcompat regressions, module shadowing, etc. The intrinsics docs were accidentally referring to some methods on f64 as std::f64, which I changed due to being contrary with how we normally disambiguate the shadow module from the primitive. In one other place I changed std::u8 to std::ops since it was just testing path handling in macros.
For places which have legitimate uses of the old consts, deprecated attributes have been optimistically inserted. Although currently unnecessary, they exist to emphasize to any future deprecation effort the necessity of these specific symbols and prevent them from being accidentally removed.
Enhance `redundant_pattern_matching` to also lint on `std::net::IpAddr`
Follow-up to #6339
r? `@ebroto`
(note: also contains a small cleanup of the other ui tests)
changelog: Enhance [`redundant_pattern_matching`] to also lint on `std::net::IpAddr`
Added known problem to comparison_chain docs
changelog: Added documentation to comparison_chain that explains a possible performance penalty, according to issue #5354
This is my first PR, I hope everything has been done correctly.
Fixes#5354
Rustup?
Basically a rustup from an unknown source. I added a regression test (and slightly changed the lint), so this'll need a review.
changelog: Fix bug in [`items_after_statements`] wher it triggered, if items were separated by trailing semicolons.
Add suspicious_operation_groupings lint
This is my (<del> currently WIP </del>) attempt to close#6039.
changelog: Added `suspicious_operation_groupings` lint.
